David–
Yes, the Marc Pro improves recovery.
Here is some info on the differences between a Marco Pro and a TENS unit.
Each has different goals when addressing a situation.
A Marc Pro will facilitate and enhance muscle performance and recovery.
TENS is a pain management device not a muscle performance/recovery device.
from Marc Pro:
Since all muscles contractions essentially “look” the same (the muscle contracts) … your observation that the contractions produced by a MARC PRO unit look the same as contractions produced by TENS unit is correct.
In fact, if you have ever been shocked by a faulty electrically wire in your home … the contraction produced by that encounter would also  “look” the same. That said, the contraction produced by that faulty wire (or a TENS) would not “feel” the same. Additionally, if you continued “shocking” yourself with that faulty wire (or a TENS) you would eventually fatigue/damage the involved muscle. My point is this; if you want to fatigue a muscle, MARC PRO is the wrong tool. MARC PRO will not fatigue your muscle (instead, it will facilitate and enhance muscle performance and recovery).

Important additional point, since TENS is not designed (or cleared by the FDA) to facilitate and enhance muscle performance and recovery and MARC PRO is, it is unfair to compare results between the two devices (TENS is a pain management device not a muscle performance/recovery device).

Here is a related article that Gary Rein from Marc Pro and others wrote for the Journal of Exercise Physiology.
The Marc Pro Device is a Novel Paradigm Shift in Muscle Conditioning, Recovery and Performance

When you order a Marc Pro recovery device and you mention “Warriors” or “KSTAR” at check out you will get 5% off and the Resiliency Project will get credit for the purchase. The Resiliency Project is a collaborative effort to help our service members. Marc Pro generously agreed to donate one conditioning device for every four they
sell when buyers mention or use the code Warriors, KSTAR.
There is a 12 month payment plan and 30 day 100% money back guarantee.

If you have questions on anything feel free to message or email me [email protected]